Ginkgo biloba supplements decrease the production of the testosterone-inhibiting hormone prolactin in the body, according to Taiwanese researchers in Hormones & Behavior. Ginkgo probably increases the dopamine levels in the brain. Dopamine inhibits the release of prolactin.

The Taiwanese tested male rats, which were given ginkgo daily for four weeks. The researchers used four groups of animals, which were administered zero, 10, 50 or 100 mg of ginkgo per kg body weight per day. During the month the researchers put the male rats together with female rats and recorded the number of times they had sex. The figure on the right shows the number of times the rats had sex during the last day of the test.

Because the researchers wanted to know how ginkgo stimulates the sexual behaviour of rats, they measured the testosterone and prolactin levels. The effect was most clear in the group of animals that had received 50 mg per kg body weight a day.

In high concentrations, prolactin inhibits the production of testosterone. But even when prolactin levels are too low to reduce the production of testosterone, prolactin can still reduce the sex drive. When the researchers examined the brains of the rats in the 50 mg group, they discovered higher concentrations of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid. The Taiwanese researchers think that this is why ginkgo acts as a prolactin inhibitor. They also tested whether ginkgo influences the production of testosterone in the testes directly, but the results were inconclusive.

Ginkgo biloba supplements decrease the production of the testosterone-inhibiting hormone prolactin in the body, according to Taiwanese researchers in Hormones & Behavior. Ginkgo probably increases the dopamine levels in the brain. Dopamine inhibits the release of prolactin.

The Taiwanese tested male rats, which were given ginkgo daily for four weeks. The researchers used four groups of animals, which were administered zero, 10, 50 or 100 mg of ginkgo per kg body weight per day. During the month the researchers put the male rats together with female rats and recorded the number of times they had sex. The figure on the right shows the number of times the rats had sex during the last day of the test.

Because the researchers wanted to know how ginkgo stimulates the sexual behaviour of rats, they measured the testosterone and prolactin levels. The effect was most clear in the group of animals that had received 50 mg per kg body weight a day.

In high concentrations, prolactin inhibits the production of testosterone. But even when prolactin levels are too low to reduce the production of testosterone, prolactin can still reduce the sex drive. When the researchers examined the brains of the rats in the 50 mg group, they discovered higher concentrations of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid. The Taiwanese researchers think that this is why ginkgo acts as a prolactin inhibitor. They also tested whether ginkgo influences the production of testosterone in the testes directly, but the results were inconclusive.

Seth Roberts cleared it up: say you weigh 220 lbs.=100Kg.. You take your weight in Kg.=100 x 10 mg. (1/5 the most effective dosage in the rat studies, in order to adjust for rats having a much greater metabolic rate)= 1000 mg. Now if your extract is a 50:1 extract (which the NOW brand is), a 60 mg. cap of extract is produced from 3 g. of Ginko--much more than the 1 g. you need.

In other words seth was saying that one 60 mg. cap/day should be enough to see prolactin inhibiting effects in anyone.